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Business Administration 3050 Midterm Exam (the return) NAME ________________ STUDENT NUMBER _________ This is a take home exam that is to be completed by yourself and is due at the beginning of class on Nov. 1. There 30 short answer questions counting 3.4 points each Special note: Right answers are hard to argue with, but well set up wrong answers can count as much or more (consideration can flow into another problem). Be sure to include the formulas that you used (or would use) when answering the questions. You may also email your instructor a spreadsheet with clearly marked answers to the exam questions (your instructor reserves the right to ignore the spreadsheet). GOOD LUCK! I have read and understand the above instructions. Signature _________________ Exhibit 1 The following is the frequency distribution for the speeds of a sample of automobiles traveling on an interstate highway. Speed Miles per Hour 50 - 54 55 - 59 60 - 64 65 - 69 70 - 74 75 - 79 Frequency 3 5 7 9 8 5 35 1. Refer to Exhibit 1. The mean is 2. Refer to Exhibit 1. The variance is 3. Refer to Exhibit 1. The standard deviation is Exhibit 2 The following represents the probability distribution for the daily demand of computers at a local store. Demand Probability 2 0 1 2 3 4 5 0.1 0.15 0.20 0.30 0.1 0.1 4. Refer to Exhibit 2. The expected daily demand is 5. Refer to Exhibit 2. The probability of having a demand for at least two computers is 6. Refer to Exhibit 2. The variance is Exhibit 3 The probability that Pete will succeed at catching fish when he goes fishing is .8. Pete is going to fish 3 days next week. Define the random variable X to be the number of days Pete catches fish. 7. Refer to Exhibit 3. The probability that Pete will catch fish on exactly one day is 3 8. Refer to Exhibit 3. The probability that Pete will catch fish on one day or less is 9. Refer to Exhibit 3. The expected number of days Pete will catch fish is 10. Refer to Exhibit 3. The variance of the number of days Pete will catch fish is Exhibit 4 The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 6. 11. Refer to Exhibit 4. The random variable x satisfies which of the following probability distributions? 12. Refer to Exhibit 4. The appropriate probability distribution for the random variable is 4 13. Refer to Exhibit 4. The expected value of the random variable x is 14. Refer to Exhibit 4. The probability that there are 9 occurrences in ten minutes is 15. Refer to Exhibit 4. The probability that there are less than 3 occurrences is Exhibit 5 The starting salaries of individuals with an MBA degree are normally distributed with a mean of $58,000 and a standard deviation of $7,500. 16. Refer to Exhibit 5. What is the probability that a randomly selected individual with an MBA degree will get a starting salary of at least $60,000? 5 17. Refer to Exhibit 5. What is the probability that a randomly selected individual with an MBA degree will get a starting salary of at less than $47,500? 18. Refer to Exhibit 5. What percentage of MBA's will have starting salaries of $53,000 to $60,000? 19. Refer to Exhibit 5. What is the probability that an MBA will have starting salaries of exactly $58,000 6 Question 20 My “colleagues” from the other side of the tracks have provided me with some “special” dice that could be particularly helpful during a craps game. My colleagues tell me that the odds of rolling a 1 is twice as high as a two and the two is twice as likely as the 3. While the odds of rolling a 4 is 1.5 times P(3) and P(5) is twice P(4) and finally, P(6) is still 1/6. Please create a cumulative probability distribution. Question 21 The travel time for a college student traveling between her home and her college is uniformly distributed between 70 and 130 minutes. Please create a cumulative probability distribution. Use 5 minutes as the delta x value. 7 Exhibit 6 A private research organization studying families in various countries reported the following data for the amount of time 4-year-old children spent alone with their fathers each day. Country Belgium Canada China Finland Germany Nigeria Sweden United States Time with Dad (minutes) 38 52 52 48 34 40 43 40 For the above sample. 22. For the problem shown in Exhibit 6. Calculate the mean (making sure to include supporting formulas) 23. For the problem shown in Exhibit 6. Calculate the standard deviation (making sure to include supporting formulas) 24. For the problem shown in Exhibit 6. Calculate the mode (making sure to include supporting formulas) 8 25. For the problem shown in Exhibit 6. Calculate the median (making sure to include supporting formulas) 26. For the problem shown in Exhibit 6. Calculate the 75th percentile (making sure to include supporting formulas) Exhibit 7 The results of a survey of 800 married couples and the number of children they had is shown below. Number of Children 0 1 2 3 4 5 Probability 0.0150 0.0623 0.1323 0.1852 0.1944 0.1633 If a couple is selected at random, what is the probability that the couple will have 27. For the problem shown in Exhibit 7. What is the probability that the couple will have less than 4 children? Be sure to include supporting calculations. 9 28. For the problem shown in Exhibit 4. What is the probability that the couple will have more than 2 children? Be sure to include supporting calculations. 29. For the problem shown in Exhibit 4. What is the probability that the couple will have more than 5 children? Be sure to include supporting calculations. 30. For the problem shown in Exhibit 4. What is the probability a couple will have 7 children. Please justify your answer. 10